This invention relates to a method and apparatus for cleaning articles, particularly articles that have been buffed with a hydrocarbon wax. The method and apparatus involve contacting a soiled article with a liquid chlorinated benzotrifluoride compound at a temperature of about 70.degree. to about 100.degree. C., followed by washing the benzotrifluoride compound off the article with liquid methylene chloride.
In the metalworking industry, metal parts are commonly buffed to enhance their appearance. The buffing compound, or rouge, typically consists of various metal oxides dispersed in a waxy substance. To remove the buffing compound from the parts, the parts were usually cleaned in a vapor degreaser where they were contacted with vapors of 1,1,1-trichloroethane or trichloroethylene. Because these solvents boil at 74.degree. and 86.degree. C., respectively, they are ideal for melting and removing buffing compounds from the parts, yet they do not become so hot that they "set" the buffing compound or oxidize the metal surface (as perchloroethylene would, which boils at 121.degree. C.).
However, 1,1,1-trichloroethane has been found to cause depletion of ozone in the stratosphere and its use in degreasers has now been made illegal. Trichloroethylene is also outlawed in many states as it is a photochemical oxidant. At the present time no good substitutes have been found to replace these two solvents.